The present invention relates to a method of and to an apparatus for pallet handling, and is particularly concerned with the handling of pallets in a live storage warehousing and order-picking system.
In an order-picking system, bulk or multiple packages of products, such as loaded pallets, are broken down into individual customer orders which may comprise either a single product, a plurality of different products retrieved from different bulk packages or pallets of products.
Order picking is generally carried out by an operator moving along an order-picking aisle, one side of which is bounded by a conveyor belt moving in the longitudinal direction of the aisle, and the other side of which is bounded by a xe2x80x9cpicking facexe2x80x9d. The picking face is constituted by the ends of a number of live storage lanes arranged perpendicularly to the picking aisle, each of the live storage lanes comprising feed means to receive one or more pallets loaded with goods. Loaded pallets are provided to the live storage lanes at their entry ends remote from the picking face, and the feed means moves the pallets towards the picking face to present them at the picking fac in a xe2x80x9cfirst-in-first-outxe2x80x9d serial order. The live storage lanes may be provided with sensors at their entry ends which detect the presence or absence of a loaded pallet at the entry end position. In response to the sensor output, an automated loading means retrieves a loaded pallet containing the correct goods for that supply lane, and placed the loaded pallet on the feed means of the supply lane so as to maintain the supply lane filled with loaded pallets.
During order picking, the operator positioned in the picking aisle removes one or more products from the loaded pallet presented at the picking face, and places them either directly on the conveyor for transport to a dispatch station, or into a container for grouping together the products of a particular customer""s order. When all the products in the customer""s order are retrieved from their respective pallets, the container is transported by the conveyor belt to the dispatch station where the order is packed and shipped. The dispatch station may be automated, or may comprise further operatives who place the order into shipping containers.
When the last product is removed from the pallet at the picking face in a supply lane, the empty pallet must be removed and disposed of, so that the feed means may present the next loaded pallet to the picking face and order picking may continue. The removal and disposal of the empty pallet often causes a difficulty for the order-picking operative, since the standard pallet is a bulky structure weighing some 30 kg.
Conventional product supply lanes comprise rollers arranged in an inclined plane falling towards the picking face, the axes of the rollers being substantially perpendicular to the direction of inclination of the plane. Pallets placed on the rows of rollers move down the inclined plane towards the picking face. A releasable arrester is provided in the supply lane, spaced from the picking face by a distance slightly greater than the corresponding dimension of a pallet. A stop means is provided at the end of the supply lane, to position a pallet at the picking face. When loaded pallets are placed on the rollers at the entry end of the supply lane, the first loaded pallet will move down the rollers to contact the arrester. Subsequent loaded pallets placed in the supply lane move down to abut the pallet which is stopped by the arrester. To present a pallet to the picking face, the operative releases the arrester to allow one pallet to pass, the arrester then engaging the second pallet to prevent its passing. The first pallet moves down to the picking face and contacts the stop means, ensuring that it is correctly positioned for order picking. The arrester is so positioned that there is a clearance between the pallet at the picking face and the next pallet in the supply lane.
When the pallet at the picking face is empty, the operative lifts the edge of the pallet nearest to him to bring the pallet into a vertical position with the upper face of the pallet directed away from the operative. The pallet is then moved along the order picking aisle to a return lane, where the operative must then place the pallet horizontally (and preferably manhandle it so as to place it with its upper face uppermost) so that it can be engaged and removed by a load handling apparatus such as a fork truck or crane. Conventionally, the same load handling apparatus which brings loaded pallets to the supply lanes is used to remove empty pallets from the return lane. When several pallets are present in the return lane, the operative may have to lift the pallet through a considerable distance so that it can be placed on top of the stack of pallets in the return lane. The operative might also have to manhandle each pallet so that its upper surface is uppermost to enable the load handling apparatus to lift the stack of pallets.
In a typical installation, a return lane is provided to serve a number of supply lanes, typically from one to ten or more. In a typical installation a return lane is provided for each ten or so supply lanes and thus the maximum distance which the operative must transport the pallet is equal to the width of approximately 5 supply lanes. Since the typical dimensions of a pallet are one meter wide by 1.2 meters long, and the width of each supply lane is approximately one meter, this manual handling of the empty pallets is tiring for the operative and represents a risk of injury to the operative, particularly if the operative has to carry each pallet a distance of up to five meters, and then form a stack of five or more pallets in the return lane.
It is an object of the present invention to provide a pallet handling apparatus for a return lane in a live storage system wherein a plurality of pallets may be arranged by an operative without having to lift any of the pallets, and the pallets may then be correctly presented for removal by a load handling apparatus.
It is also an object of the present invention further to provide a pallet handling apparatus which does not require any external power source, but orients the pallets correctly under gravity alone.
The present invention provides a live storage system comprising a number of supply lanes and a return lane, the return lane comprising a pallet orienting apparatus for presenting empty pallets for removal by a load handling apparatus.
In the method of the present invention at least one empty pallet is moved to a substantially vertical position, placed in a pallet orienting device in a first, substantially vertical, orientation and rotated by the pallet orienting device to a second, substantially horizontal position. Preferably, the method provides for a number of pallets to be arranged in a row with each pallet in a substantially vertical plane, and for the row of pallets to be rotated to form a stack or pile of pallets with each pallet in a substantially horizontal plane.
In a development of the system and method, empty pallets may be raised to a substantially vertical position by powered or power-assisted lifting devices.